Fukuda H, Fukai K
Brain Res. 1986 Aug 20;380(2):276-86. doi: 10.1016/0006-8993(86)90223-4.
In decerebrate dogs, stimulation of pelvic afferent fibres and distension of the rectum, vagina and urinary bladder brought about a sustained postural change and rhythmic abdominal compression. The posture, which resulted from flexion of the back and stifle joints, extension of the hip joints and lifting of the tail, was rhythmically intensified with the abdominal compression. The sustained and rhythmic postural changes are similar to those observed in conscious dogs during defaecation. Intratracheal pressure increased with the abdominal compression. Nervous outflow to the muscles of the glottis, diaphragm, abdominal wall, tail and rear legs changed as would be expected from both the postural changes and the increases in intratracheal and intra-abdominal pressure. Nervous outflow to the external sphincter muscles of the anus and urethra increased simultaneously with both kinds of postural change; however, the increased outflow to the anus was suppressed when defaecation was initiated, and the outflow to the urethra was suppressed when micturition was initiated. In about one-third of the dogs, decreases in the outflow of the pelvic rectal branch and slight increases in the outflow of the vesical branch occurred synchronously with the abdominal compression. These results show that postural change and straining for defaecation, micturition and parturition are reflexly organized by the lower brainstem and the spinal cord.
在去大脑的狗身上，刺激盆腔传入纤维以及直肠、阴道和膀胱扩张会引起持续的姿势改变和有节奏的腹部压迫。由背部和膝关节屈曲、髋关节伸展以及尾巴抬起所导致的姿势，会随着腹部压迫而有节奏地加剧。这种持续的和有节奏的姿势改变与清醒狗排便时观察到的相似。气管内压力随着腹部压迫而升高。声门、膈肌、腹壁、尾巴和后腿肌肉的神经传出活动发生了变化，这与姿势改变以及气管内和腹内压力的升高所预期的情况一致。肛门和尿道外括约肌的神经传出活动在两种姿势改变时同时增加；然而，开始排便时肛门的传出活动增加会受到抑制，开始排尿时尿道的传出活动会受到抑制。在大约三分之一的狗中，盆腔直肠支的传出活动减少以及膀胱支的传出活动轻微增加与腹部压迫同步发生。这些结果表明，排便、排尿和分娩时的姿势改变和用力是由低位脑干和脊髓反射性组织的。
